WO2004095496A1 - Plasma display panel and method for producing same - Google Patents

Abstract

A plasma display panel is disclosed wherein the sustaining voltage is stabilized and decrease in phosphor luminance is suppressed. In the plasma display panel, a magnesium oxide (MgO) protective film (14), to which an oxide having an electronegativity of not less than 1.4 is added, is formed on a dielectric glass layer (13) as the magnesium oxide (MgO) protective film (14). Consequently, adsorption of impurity gases onto the protective film (14) can be suppressed, and therefore the sustaining voltage is stabilized and decrease in phosphor luminance is suppressed.

Description

 Description Plasma display panel and method of manufacturing the same

 The present invention relates to a plasma display panel used for a display device and the like, and a method for manufacturing the same, and more particularly to a high-performance magnesium oxide (MgO) protective film. Background art

In recent years, among color display devices used for image display such as computers and televisions, a plasma display device using a plasma display panel (hereinafter, referred to as a PDP or panel) has been realized to be large, thin, and lightweight. An AC surface-discharge PDP, which is a typical AC-type PDP that has attracted attention as a possible display device, consists of a front plate consisting of a glass substrate formed by arranging scan electrodes and sustain electrodes that perform surface discharge, and a data electrode. A back plate made of an array of glass substrates is placed in parallel and opposed to each other so that both electrodes form a matrix, and a discharge space is formed in the gap. It is configured by sealing. Then, between the substrates, discharge cells partitioned by partition walls are provided, and a phosphor layer is formed in a cell space between the partition walls. In a PDP having such a configuration, a gas discharge causes ultraviolet rays to be generated, and this ultraviolet ray excites phosphors of red (R), green (G), and blue (B) to emit light, thereby providing color display. It is carried out. In such an AC surface discharge type PDP, a dielectric layer is provided to cover the electrodes of the front plate, and a protective film made of magnesium oxide (MgO) is provided to protect the dielectric layer. . The protective film is required to have high electron emission capability and sputter resistance, and a technology for modifying the surface of the protective film has been disclosed (for example, Japanese Patent Application Laid-Open No. 9-2555552, Japanese Unexamined Patent Application Publication Nos. Hei 8-236028, Japanese Patent Laid-Open No. 2000-57939, Japanese Patent Laid-Open No. 2000-76989).

In such an AC surface discharge type PDP, magnesium oxide (MgO) as a protective film has the following problems. In other words, magnesium oxide (MgO) has a low electronegativity of magnesium, so its crystal has a strong ionic property and tends to have a positive charge property. Usually, there are many irregularities and crystal defects at the magnesium oxide (MgO) interface, and the positive charges of Mg ions are exposed everywhere in these defects. Therefore, PD P with the various processing in the manufacturing process to generate H ₂ 0 and C_〇 ₂ or hydrocarbon Motokei gas (decomposed product of predominantly organic binder such) is adsorbed 'about its defects discharge However, there is a problem that the voltage becomes unstable or the discharge voltage rises. These magnesium oxide (Mg O) H ₂ 0 was adsorbed to, CO 2, hydrocarbon-based gas is discharged in the panel during the discharge after the panel created, Ya adsorbed to the oxidation reaction the fluorescent surface There is a problem that a reduction reaction is caused to cause the surface of the phosphor particles to be non-crystallized, thereby lowering luminance.

Therefore, an object of the present invention is to provide a PDP with stable discharge characteristics and low luminance degradation by realizing a magnesium oxide (MgO) protective film with low gas adsorption. Disclosure of the invention In order to achieve the above object, a PDP of the present invention is provided on a first substrate, a first electrode, a dielectric glass layer provided over the first electrode, and a dielectric glass layer provided on the dielectric glass layer. A front panel having a protective film made of magnesium oxide (MgO) to which an oxide containing an element having an electronegativity of 1.4 or more is added, and at least a second layer formed on a second substrate. It has a back panel on which electrodes, partition walls, and a phosphor layer are disposed, and arranges the protective film and the phosphor layer so as to face each other, and partitions between the front panel and the rear panel with a partition wall To form a discharge space.

With this configuration, the large oxide electronegativity than magnesium oxide (M g O), can and this weaken the positive charge of the protective film, the protective film H ₂ 0 and CH _X is adsorbed This makes it possible to realize a PDP with stable discharge characteristics and little luminance degradation. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a sectional perspective view of a PDP according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a plasma CVD apparatus used when forming a protective film according to the embodiment of the present invention.

 FIG. 3 is a schematic diagram of a high frequency sputtering apparatus used when forming a protective film according to the embodiment of the present invention.

 FIG. 4 is a schematic diagram of a vacuum evaporation apparatus used when forming a protective film according to the embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 The PDP of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional perspective view of a PDP according to an embodiment of the present invention. The PDP is provided with a pair of first electrodes, ie, a discharge electrode 12 and a dielectric glass layer 13, which function as a sustain electrode and display scan, on a front glass substrate 11. Further, a protective film 14 made of magnesium oxide (MgO) is provided on the dielectric glass layer 13 to form the front panel 10. On the back glass substrate 21, a back electrode 20 is formed by providing an address electrode 22 as a second electrode, a base dielectric glass layer 23, a partition wall 24, and a phosphor layer 25. The front panel 10 and the rear panel 20 are bonded together, and a discharge gas 30 is sealed in a discharge space 30 formed between the front panel 10 and the rear panel 20.

The front panel 10 is manufactured as follows. That is, a transparent electrode is formed on the front glass substrate 11 by a sputtering method or the like and then patterned, and then a silver electrode paste is applied by a screen printing method or the like to form a discharge electrode 12. Form. Next, as to cover the discharge electrodes 1 2, lead oxide (P b O) 7 5 _{wt%, (2 0 3 B)} 1 5 wt% boron oxide, oxide硅element (S i 0 ₂₎ 1 0 wt%, such as A dielectric glass layer is applied by a screen printing method or the like to form a dielectric glass layer 13. Here, the screen-printed paste is solidified through a firing step. Next, a magnesium oxide (MgO) protective film 14 to which an oxide containing an element having an electronegativity of 1.4 or more and having a negative charge was added was formed by plasma CVD, high frequency sputtering, and vacuum deposition. It is formed on the dielectric glass layer 13 by using a method or an ion plating method.

On the other hand, back panel 20 is manufactured as follows. That is, a silver electrode paste is screen-printed on the rear glass substrate 21 to form an address electrode 22. A lead-based glass paste is applied by a screen printing method or the like so as to cover the electrode electrode 22, and a base dielectric glass layer 2 is applied. Form 3. Next, in order to form the barrier ribs 24 at a predetermined pitch, an insulating material paste is applied and then patterned to form the barrier ribs 24. Note that, similarly to the formation of the front panel 10, the paste is solidified through a firing step. Next, a red phosphor, a green phosphor, and a blue phosphor are provided in each space between the partition walls 24 to form a phosphor layer 25. The phosphor of each color, but can generally be used a phosphor used in the PDP, where a red phosphor _{(YxG d, - x) B0} 3: E u 3+, green phosphor is a Z n ₂ S i 0 _4: is used E u ^2+: Mn ^2+, B is a blue phosphor _{a M g a 1 10 O 17} .

Next, the front panel 10 and the rear panel 20 thus manufactured are bonded to each other using sealing glass so that the discharge electrode 12 and the padless electrode 22 are orthogonal to each other. Then, after evacuating the partitioned discharge spaces 3 in 0 by a partition wall 24 to a high vacuum ^{(8 X 1 0- 7 T orr} ), PD P by encapsulating the discharge gas having a predetermined composition at a predetermined pressure Is prepared.

 In the present embodiment, the cell size of the PDP is 0.2 mm or less and the distance between the discharge electrodes 12 is 0.1 mm or less so as to be suitable for a 40-inch class high-definition television. Has formed. The partition 24 has a double-girder structure having the partition 24 between cells orthogonal to the direction of the address electrode 22 in order to improve luminance.

In addition, the composition of the discharge gas to be filled is the Ne-Xe system conventionally used, but the content of Xe is set to 10% by volume or more, and the filling pressure is set to 400 Torr. By setting it in the range of ~ 760 Torr, the concentration of Xe is increased, and the light emission luminance of the cell is improved. Next, a method for forming a magnesium oxide (MgO) protective film will be described. First, a method of forming by a plasma CVD method will be described. FIG. 2 is a schematic diagram of a plasma CVD apparatus used for forming a protective film.

The plasma CVD apparatus 40 heats a glass substrate 47 consisting of a front glass substrate 11 on which a discharge electrode 12 and a dielectric glass layer 13 are formed in a plasma CVD apparatus main body 45. 46 are provided. The inside of the plasma CVD device main body 45 can be depressurized by an exhaust device 49, and a high-frequency power supply 48 for generating plasma is installed in the plasma CVD device main body 45. . In addition, a power source 50 for applying a bias with the glass substrate 47 as a negative electrode is provided. An argon (Ar) cylinder 41 a, 4 lb is provided outside, and supplies argon (Ar) gas as a carrier gas to the plasma CVD system body 45 via the vaporizers 42 and 43. are doing. In the vaporizer 42, a metal chelate as a raw material of magnesium oxide (MgO) and an oxide added thereto is heated and stored. By blowing argon (Ar) gas from an argon (Ar) cylinder 41a, the metal chelate can be evaporated and sent to the plasma CVD apparatus body 45. Further, in the vaporizer 43, magnesium oxide (Mg〇) and an acetylaceton-cyclopentene genenyl compound as a raw material of an additive are heated and stored. By blowing argon (Ar) gas from 4 lb of argon (Ar) cylinder, this acetyl-aceton-cyclopentagenenyl compound can be evaporated and sent to the plasma CVD device body 45. ing. Furthermore, oxygen (0 ₂₎ cylinder 44 is to supply feed oxygen (0 ₂₎ is the reaction gas into the plasma CVD apparatus main body 45. When performing plasma CVD using the plasma CVD apparatus 40 having the above configuration, the heating temperature of the glass substrate 47 by the heater section 46 is set to a constant temperature within a range of 250 ° C. to 380 ° C. Then, the internal pressure of the reaction furnace is reduced to 30 Pa to 300 Pa using the exhaust device 49. By driving the high-frequency power supply 48 and applying a high-frequency electric field of, for example, 13.56 MHz, plasma is generated in the plasma CVD apparatus main body 45, and the raw material gas sent into the furnace is chemically converted. An extremely active radical atom is generated, and a protective film 14 is formed while depositing a chemical reaction product on the substrate.

Here, the vaporizer 42 or the vaporizer 4 3 metal chelate Contact and Shikuropen evening Jeniru compound supplied from, for example, as a raw material of Mg M agnesi um D ipivaloyl Me thane [M g (C Π Η 19 0 2) _{2], M agnesium A cety 1} acetone [Mg (C 5 H 7 0 2) 2], C yclopentadienyl M agnesi um [Mg (C 5 H 5) 2], M agnesi um T rif 1 uoroacetylacetone [Mg (C 5 H ₅ F ₃ 0 ₂ ) ₂ ] can be used. In addition, Ti, Zr, Ge, V, Nb, Ta, Sb, Cr, Mo, and W, which are elements M for adding an oxide containing an element having an electronegativity of 1.4 or more , S n, B, S i , P b, as a raw material of M n, D ipiva 1 oy 1 Me tane [M (C,! ^ [19 0 2) J, a cetylacetone [M (C 5 H 7 0 _{2) J, T rifluoroacetylacetone [M} (C 5 H 5 F 3 0 2) J , or the like can be used. When an oxide is added to magnesium oxide (MgO) using such a raw material, the molar ratio of the raw material of Mg and M is set to be 1: 0.0000 005 to 0.005. Mix and use as raw materials. The amount of oxide added is controlled by controlling the molar ratio of M and the temperature of the vaporizer. Such raw materials The protective film 14 is formed by a plasma CVD method in which a negative bias is applied to the substrate by using an oxide containing an element with an electronegativity of 1.4 or more in the magnesium oxide (MgO) protective film 14. Can be added.

 The reason why the electronegativity of the element of the oxide to be added is 1.4 or more is that the electronegativity of magnesium in magnesium oxide (MgO) is 1.25 and is higher than that. The electronegativity of the (MgO) protective film 14 can be increased. In addition, since oxides containing an element having an electronegativity of 1.4 or more generally show negative charge, it is easy to control the chargeability of the protective film 14 by controlling the amount of addition. It becomes.

 Next, a method of forming the protective film 14 by a high frequency sputtering method will be described. FIG. 3 is a schematic diagram of a high-frequency sputtering device used when forming the protective film 14.

The sputtering device 70 includes a sputter device main body 65 in which a glass substrate 67 comprising a front glass substrate 11 on which a discharge electrode 12 and a dielectric glass layer 13 are formed is heated. 66 is provided, and the inside of the sputtering device body 65 is configured to be able to be depressurized by the exhaust device 69. Further, a high-frequency power source 68 for generating plasma is installed in the sputter device body 65. The high-frequency power supply 68 was obtained with the addition of magnesium oxide (MgO) and an oxide containing an element with an electronegativity of 1.4 or more, from 0.005 mol% to 5 mol%. Installed. A power supply 64 for applying a negative bias to the glass substrate 67 is provided. Argon (Ar) cylinder 62 is argon (Ar) gas The scan, oxygen (0 ₂₎ cylinder 6 3 is adapted to supply oxygen (0 ₂₎ as a reactive gas to the sputtering evening device body 6 5.

When performing the sputtering using the sputtering apparatus 70 having the above configuration, the glass substrate 67 is placed with the dielectric glass layer 13 facing upward, and the glass substrate 67 is placed at 250 ° (: up to 380 °). ° heated to C. Furthermore, argon (a r) 0 pressure with an exhaust system 6 9 while introducing gas and oxygen (〇 ₂₎ gas into the sputtering apparatus body 6 5. l P a~ 1 0 P a The high-frequency power supply 68 is driven to form a protective film 14 of magnesium oxide (MgO) while generating plasma in the sputtering device body 65. Here, the power supply 64 is connected. When the target 61 is sputtered while applying a potential of -100 V to -150 V to the glass substrate 67 to form the protective film 14, the film forming speed and film forming characteristics are further improved. The control of the amount of the oxide containing the element with a high electronegativity in the magnesium oxide (MgO) protective film was controlled by the following method. It can be controlled by the amount and RF power Tsu bets 6 oxides and place in 1.

Next, a method of forming the protective film 14 by a vacuum evaporation method will be described. FIG. 4 is a schematic view of a vacuum deposition apparatus used for forming the protective film 14. In the vacuum evaporation apparatus 80, a glass substrate 87 comprising a front glass substrate 11 on which a discharge electrode 12 and a dielectric glass layer 13 are formed is heated and heated in a vacuum evaporation apparatus body 85. 1 is provided. Further, the inside can be reduced in pressure by an exhaust device 89. In addition, an evaporation source 86 of an electron beam cathode for evaporating magnesium oxide (MgO) and an oxide as an additive is provided. The oxygen (O ₂ ) cylinder 82 is used as a reaction gas, and supplies oxygen (O ₂ ) gas into the vacuum evaporation apparatus main body 85. Using a vacuum deposition device 8 0 of the above configuration, when performing deposition, place the glass substrate 8 7 a dielectric glass layer 1 3 facing downward, oxygen (0 ₂₎ vacuum evaporation apparatus body 8 5 gas to While introducing, the pressure is reduced to 0.01 P a to l. OP a using the exhaust device 89. Further, the protective film 14 is formed by evaporating the magnesium oxide (MgO) to which the additive is added in an amount of 0.0005 mol% to 0.5 mol% by an electron beam or an evaporation source 86 of a hollow sword. Can be formed.

The magnesium oxide (MgO) protective film formed by the conventional vacuum evaporation method (EB method) is formed using high-purity magnesium oxide (Mg.O) of approximately 99.99%. Is filmed. However, magnesium oxide (MgO) itself has low electronegativity and high ionicity. Therefore, the Mg ⁺ ions on the surface show a high state of unstable energy with locally exposed charge, and stabilize by adsorbing ionic substances such as hydroxyl groups (OH- groups). Further, cathode of the formed magnesium oxide (MgO) - According to de luminescence measurements, along with the peak of the number of luminescent Ssensu based on oxygen defects are observed, these defects H ₂ 0 and C_〇 ₂ or carbonized It is also the point of adsorption of hydrogen-based gas.

In order to reduce the adsorption points based on these local positive charges, it is necessary to reduce the strong ionic bonds of magnesium oxide (MgO) with low electronegativity. For this purpose, oxides containing elements with high electronegativity and strong covalent bond, that is, low ionic bonds, especially oxides containing elements with electronegativity of 1.4 or more and having negative chargeability, must be used. It can be added to reduce strong ionic bonds. That is, a part of the magnesium oxide (MgO) crystal, by placing M- 0 bond different co sexual combined with strong Mg- 0 bonds ionic bond, H ₂ '0 and C0 ₂ or C The adsorption properties of H _x changes, defects in the magnesium oxide (MgO) control is your be because gas adsorption points has decreased less.

By reducing the adsorption of various gases this way to magnesium oxide (Mg_〇), and stabilization of the sustaining voltage, the oxidation of impure gas _{(H 2 0, C 0 2} , CH X , etc.) by the phosphor Thus, the problem of luminance degradation due to the reduction reaction can be solved.

 An oxide containing an element with an electronegativity of 1.4 or more and 2.55 or less was confirmed to be effective in reducing gas adsorption, stabilizing discharge sustaining voltage, and suppressing luminance deterioration. ing.

 【Example】

 Hereinafter, examples of evaluation results using samples manufactured by the above method will be described.

Table 1 shows the characteristics of PDP when various oxides containing elements with high electronegativity were added to the magnesium oxide (MgO) protective film by changing the film formation method. The PDPs of Sample No. 1 to Sample No. 6 shown in Table 1 were prepared by the plasma CVD method based on the above-described embodiment, and were oxidized by adding an oxide having an electronegativity of 1.4 or more. It has a magnesium (MgO) protective film. The cell size of the PDP is set to match the 42-inch high-definition television display. The height of the partition walls 24 is set to 0.12 mm, and the interval (cell pitch) between the partition walls 24 is set to 0.15 mm. Were arranged, and the distance between the discharge electrodes 12 was 0.06 mm. The dielectric glass layer 1 3 lead system 6 5 wt% of lead oxide (P bO) 2 5 wt% of boron oxide and (B ₂ 0 ₃₎ 1 0% by weight of silicon oxide (S i 0 ₂ ) and an organic binder (100% ethylcellulose dissolved in quinone-pineol) are screen-printed. It was formed by baking at 52 ° C. for 10 minutes after coating by a method, and the film thickness was 30 m.

The plasma CVD apparatus is a pressure in the reaction vessel with 3 0 pa~ 3 0 0 P a , argon (A r) gas flow rate 1 L / min, the flow rate of oxygen (0 ₂₎ together as a 5 L / min 0.1 The flow was performed for 1 minute, the application of high frequency was performed at 300 W to 500 W for 1 minute, and the deposition rate was adjusted to 0.9 mZ. The thickness of the magnesium oxide (MgO) protective film to which an oxide containing an element having an electronegativity of 1.4 or more is added is 0.9 m, and the amount of the oxide added is 0.5 mol% or less (5 0.000 pm or less), preferably in the range of 0.05 mol% to 0.5 mol%. If the amount of the oxide actually added is within the above range, the effect is not so sensitive and a clear effect is found. Table 1 also shows the electronegativity of the added oxide element and its tendency to charge.

 Sample No. 7 to Sample No. 9 are protective films formed by high frequency sputtering, and Sample No. 10 to Sample No. 14 are protective films formed by vacuum evaporation. . For sample No. 15 * and sample No. 16 *, as a comparative example, a conventional magnesium oxide (MgO) protective film to which no oxide containing an element having a large electronegativity was added was vacuumed. The film was formed by vapor deposition and high frequency sputtering.

Table 1 shows the rate of change in the sustaining voltage and the rate of change in luminance as PDP evaluation results. The sustaining voltage, which is greatly affected by the performance of the magnesium oxide (MgO) protective film covering the discharge electrode, is the voltage immediately before the discharge is extinguished by lowering the sustaining voltage after the PDP starts discharging. The brightness corresponds to the brightness of the entire panel obtained when white is set at a predetermined color temperature under a constant driving condition. In other words, the entire surface controlled by the phosphor with the largest luminance degradation among the three primary color phosphors expressing white. This is the luminance of white display, measured as a value when driven at a frequency of 200 kHz. The rate of change of the discharge sustaining voltage and luminance was determined by applying a discharge sustaining pulse of a voltage of 175 V and a frequency of 200 kHz to the PDP for 100 hours continuously, and the discharge sustaining voltage before and after that. The change in luminance was measured, and the rate of change for each was determined as (value after application-value before application) value before Z application * 100.

 【table 1】

* Sample Nos. 15 and 16 are comparative examples Table 1 shows that the PDPs of Sample No. 1 to Sample No. 14 to which the oxide according to the present invention was added had a change rate of the discharge sustaining voltage after lighting for 100 hours of 1% to 2%. Compared to the conventional PDP, the discharge sustaining voltage of the PDP of the conventional magnesium oxide (MgO) protective film No. 15 * and No. 16 * was close to 10% due to adsorption contamination on the film surface. You can see it is rising. In addition, the change rate of the luminance after the panel was lit for 1000 hours was about 13% worse in Sample No. 15 * and Sample No. 16 *, but the oxide was added. In the PDPs of Sample No. 1 to Sample No. 14, the deterioration was suppressed to 14% to 16%. This confirms that the PDPs of Sample No. 1 to Sample No. 14 reduced the impurity gas adsorption of magnesium oxide (Mg〇) in the panel. Industrial applicability

 According to the present invention, magnesium oxide (Mg〇) to which an oxide containing an element having an electronegativity of 1.4 or more is added as a magnesium oxide (MgO) protective film covering a discharge electrode of each light emitting cell. Since a protective film is used, it is possible to provide a PDP that solves the problem of adsorption of impurity gas by the protective film, suppresses a change in the discharge sustaining voltage, and significantly reduces luminance degradation. It becomes possible.

Claims

The scope of the claims 1. a first electrode on a first substrate; a dielectric glass layer provided over the first electrode; and an electronegativity provided on the dielectric glass layer of 1.4 or more. A front panel including a protective film made of magnesium oxide (MgO) to which an oxide containing an element is added;  A back panel on which at least a second electrode, a partition, and a phosphor layer are provided on a second substrate;  A plasma display panel in which the protective film and the phosphor layer are arranged so as to face each other, and a discharge space partitioned by a partition is formed between the front panel and the rear panel. 2. The plasma display panel according to claim 1, wherein the oxide is a negatively charged oxide. 3. oxide, titanium oxide (T i 〇 _2), zirconium oxide (Z r 0 _2), germanium oxide (G e 0 _2), vanadium oxide (V ₂ 0 _5), niobium oxide (N b ₂ 0 _5), tantalum oxide (T a ₂ 0 _5), antimony oxide (S b ₂ 0 _5), chromium oxide (C r ₂ 〇 _3), molybdenum oxide (Mo 0 _3), oxide Tandasute down ( W0 _3), tin oxide (S N_〇 _2), boron oxide (B ₂ 0 _3), silicon oxide (S i 〇 _2), lead oxide (P b O), or manganese oxide (Mn_〇 ₂₎ 1 3. The plasma display panel according to claim 2, wherein the plasma display panel is a kind or more. 4. forming an electrode on at least the first substrate; forming a dielectric glass layer over the electrode; and covering the dielectric glass layer with an element having an electronegativity of 1.4 or more. Forming a protective film made of magnesium oxide (MgO) to which the oxide containing is added,  A method of manufacturing a plasma display panel, wherein the step of forming the protective film is any one of a plasma CVD method, a sputtering method, a vacuum evaporation method, and an ion plating. 5. The step of forming a protective film includes: In a reaction vessel of 300 Pa to 300 Pa, an organometallic compound of magnesium and an organometallic compound of a metal contained in an oxide containing an element having an electronegativity of 1.4 or more are mixed with oxygen ( 0 ₂₎ and argon (producing method of a plasma di splay panel according to claim 4, characterized in that a r) is a flop plasma CVD method is used for the reaction of.